Alcoholysis method and device system for producing dioctyl terephthalate from polyester waste

Abstract

The invention discloses an alcoholysis method and a device system for preparing dioctyl terephthalate by polyester wastes. The alcoholysis method comprises the steps as follows: continuously adding measured octanol, polyester wastes in different forms and catalyst into an alcoholysis reaction kettle; after the alcoholysis reaction, feeding generated ethanediol and octanol into a distillation tower; discharging from the top of the tower; cooling by a condenser at the top of the tower; feeding into a secondary specific absorption and separation tank; fully absorbing ethanediol by water; refining and dehydrating water-insoluble octanol by a rectification device; and returning into the reaction kettle for continuing to participate in reaction. The alcoholysis method can adapt to production of dioctyl terephthalate by the polyester wastes in different forms; ethanediol is fully absorbed; refined and recovered octanol is dehydrated; the conversion rate of the polyester wastes is increased; the reaction time is shortened; and the productivity of a device is improved.

Description

technical field [0001] The present invention relates to a production method and device system of a plasticizer, in particular to a new high-efficiency production process and device system for producing dioctyl terephthalate (dioctyl terephthalate) with various polyester wastes and octanol as raw materials DOTP). Background technique [0002] With the rapid increase in the amount of polyethylene terephthalate (PET polyester), more and more waste PET polyester is discharged into nature. Because of its strong chemical inertia, it is difficult to be absorbed by air or microorganisms. Degradation will have a great impact on the environment. Therefore, the recycling of waste PET polyester is increasingly valued by the world. The production of dioctyl terephthalate (DOTP) from waste PET polyester with isooctyl alcohol (2-EH) is one of the most important aspects in its recycling, which can improve the utilization of waste polyester rate, turning waste into treasure, in order to in...

AI Technical Summary

Problems solved by technology

This process basically meets the production requirements, but there are also the following problems: First, the raw materials used must be in the form of solid particles. For a large amount of PET filamentous and cloth-like wastes, the reaction can only be carried out above the boiling point of octanol, and it is impossible to organize an effective continuous process. production; the second is that the ethylene glycol absorption tank adopts a simple absorption tank and only has one-stage absorption. The absorption effect of ethylene glycol is poor, and the ethylene glycol that cannot be absorbed returns to the alcoholysis reactor together with octanol, thus affecting the chemical The reaction balance moves, which reduces the conversion rate of raw materials and increases the consumption of raw materials; the third is that the octanol overflowed from the ethylene glycol absorption tank returns to the alcoholysis reactor without any treatment, and the water entrained in octanol Also return to the reactor together, the presence of water will hydrolyze the catalyst on the one hand and deactivate part of the catalyst;

[0006] Therefore, a new production process and device system is needed, which not only ensures continuous feeding and continuous production of a large amount of PET filamentous and cloth-like waste, but also effectively separates and absorbs ethylene glycol, while avoiding octanol entrained water from returning to the reactor partial catalyst deactivation

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